Respirators providing for a breathable air supply to a wearer are well known and have been used for many years. Such masks are used by firefighters, in the military, and industries where the air supply may be contaminated. In addition to providing a clean air source to the nose and mouth for breathing, full face shields also provide a seal to protect the eyes and face from harmful or irritating gases and other substances. Such masks typically include a transparent face shield and may also include mounts for accepting detachable and replaceable filter elements or connectors to air supplies. Such mounts often are threaded connectors that require considerable time and effort to attach and detach and do not provide a stop at a positive locking position.
It can be appreciated that the utility of such a mask is increased if the visual range of the wearer has minimal obstructions. Therefore, the size of the transparent face shield should be maximized. Prior full face shields have provided sufficient coverage to the face but have failed to provide a sufficiently large visual range. Attachment devices for the breathable air source have typically been mounted into a nontransparent rubber portion extending upward at the bottom of the mask, thereby reducing the size of the lens portion and the viewing area at the bottom portion of the face shield. Because of the weight of detachable filters or air hoses and connectors, it is usually necessary to increase the thickness of the respirator body surrounding the inhalation ports to provide sufficient rigidity to hold the air source connector or filter cartridge in position, resulting in additional weight added to the mask. The elimination of thick rubber attachment portions decreases the overall weight of the mask providing better comfort for the wearer. It can be appreciated that when such full face respirator masks are worn for extended periods of time, the weight of the mask and comfort for the wearer have increased importance.
An example of a full face respirator mask is North Safety Equipment's Model 7600 series respirator. The full facepiece of North has orifices formed therethrough for receiving breathable air. The orifices, however, require the attachment of separate mounting hardware mechanically attached to the facepiece for connecting to a breathable air source. The North facepiece requires a separate cartridge connector and a grommet mounting to the facepiece for mating to a connector of a breathable air source. If the connector pieces are not properly tightened, the mask may leak or the connector assembly may rotate in the orifice. Some filter cartridges are oriented to a specific position and may become misaligned should they rotate, possibly impairing the wearer's visual field.